Audio content tends to have a high peak to average ratio, also referred to here as crest factor or peak to average power ratio, by virtue of the nature of speech, music and movies that are intended for humans. While a dc signal has the smallest possible crest factor of 0 dB, and that of a pure or single-tone sinusoid is 3 dB, acoustic engineers who strive to produce audio systems that have improved sound fidelity may prefer relatively high crest factors in the range of 25-40 dB for example, depending upon the particular audio content being reproduced. While the audio signal peaks in such cases are relatively high, that is relative to the average of the audio signal, the peaks typically do not last very long and as such can be amplified without too much distortion by a well-designed audio power amplifier. In certain consumer electronic products, Class D power amplifiers are used because of their relatively high efficiency vs. other amplifier topologies such as linear amplifiers. Class D amplifiers are popular in portable, battery powered consumer electronic devices such as smartphones, tablet computers and notebook computers. In such audio power amplification systems, a rechargeable battery of the portable device is coupled to provide the input supply power of a voltage boost converter whose output supplies power to the audio amplifier. The converter boosts the battery voltage, so as to obtain louder sound from a speaker that is being driven by the amplifier. The voltage boost converter typically has an output boost capacitor, which acts as a filter for the regulated dc output voltage of the boost converter. The amplifier may be a Class D audio amplifier, for example, a differential h-bridge driver. The audio signal is fed to a signal input of the Class D amplifier, and the latter drives the loudspeaker with a predetermined gain. Variable volume is achieved by applying a variable full band gain to the audio signal. Typically, the voltage boost converter provides a regulated dc output voltage that remains fixed despite variations in the battery voltage and variations in the load (being the power amplifier).